There are many safety syringe designs available today. Some of these designs have a sleeve or a sheath that will cover the needle after is has been used. Some typical designs with sleeves or sheaths are Z. M. ROEHR, et al U.S Pat. No. 3,008,570, Z. M. ROEHR U.S. Pat. No. 3,107,785, BARTNER, et al U.S. Pat. No. 3,895,633, G. K. BURKE U.S. Pat. No. 3,306,291, GYURE et al U.S. Pat. No. 4,300,678, WINSTEAD HALL U.S. Pat. No. 4,356,822, SAMPSON U.S. Pat. No. 4,425,120, LARSON U.S. Pat. No. 4,639,249, HARBAUGH U.S. Pat. No. 4,655,751, STRAUSS U.S. Pat. No. 4,664,654, BRAGINETZ U.S. Pat. No. 4,666,435, SPENCER U.S. Pat. No. 4,702,738, MILORAD U.S. Pat. No. 4,702,739, SPENCER U.S. Pat. No. 4,801,295, PONCY U.S. Pat. No. 4,816,022, and HUGHES U.S. Pat. No. 4,840,619.
Other designs have a retractable needle such as WELTMAN U.S. Pat. No. 3,306,290, HAINING U.S. Pat. No. 4,790,822, and DENT U.S. Pat. No. 4,392,859. These designs do not have a means whereby the needle is extended from the syringe and held in place in a positive and rigid position in order to first inject the needle prior to injecting the medication. Still other designs have methods of bending the needle to render it harmless after the medication has been injected. Most of these designs have one major purpose and that is to prevent the spread of infectious diseases such as AIDS, hepatitis or other diseases from an accidental injection with a contaminated needle, into others after the needle of the syringe was inserted into a patient with one of the above mentioned diseases. These various designs of safety syringes all work well up to a degree, but they all fall short of the intended purpose during the act of covering the needle, or removing the needle.
All of these syringe designs require at least two hands to operate. The use of two hands to cover the contaminated needle is most unsatisfactory in that during the act of placing a second hand on the syringe the person holding the syringe in one hand may be bumped and accidently inject the needle into their other hand before the syringe can be grasped. Other accidental jabbings or injections can happen in an ambulance where just as a person tries to grasp the contaminated syringe, the ambulance can hit a bump in the road causing the person holding the syringe to accidentally stick another person or themselves with the contaminated needle. The need has developed for a syringe that will cover the contaminated needle with the use of only one hand.
There are still other types of safety syringes that are available today such as DYSARZ U.S. Pat. No. 4,973,316 and again by DYSARZ et al. U.S. Pat. No. 4,978,343 that can be operated by one hand and are further retractable, however, they are not destroyed internally. In DYSARZ, to compress the plunger to disable the syringe one must overcome the energy of a spring in order to retract the needle cannula of the syringe. There is no need to overcome the spring energy in the design of the present invention.